For example, Patent Literature 1 discloses a technique to easily and correctly specify a tracking target before or during object tracking, which is applicable to a surveillance camera system. In this technique, an object to be a tracking target is displayed in an enlarged manner and other objects are extracted as tracking target candidates. A user merely needs to perform an easy operation of selecting a target (tracking target) to be displayed in an enlarged manner from among the extracted tracking target candidates, to obtain a desired enlarged display image, i.e., a zoomed-in image (see, for example, paragraphs [0010], [0097], and the like of the specification of Patent Literature 1).